EP0968783B1 - Tool holder with radial fine positioning - Google Patents

Description

The invention relates to a rotary tool, in particular one Short clamp holder with standard inserts.

A similar tool is known from Fig. 1 of U.S. Patent 3,236,125. The The holder is directly with the fastening screw in a recess a boring bar, with a rear side edge on one the support-forming surface of the recess abuts, while one in the screw on one of the front part of the holder corresponding place of the surface of the recess abutment takes place. Will the Holder by the jack screw for radial adjustment of the Insert position more or less bent, so one occurs at the same time Swiveling the holder in its front part and through a undesired change of the so-called setting angle. To overcome this disadvantage fix, is a fundamentally different version in US Pat. No. 3,236,125 proposed a tool holder. There is no elastic here Bending the holder more, but there will be a change in the distance from a support surface on the boring bar by moving one in it Dimension about the holder corresponding wedge piece, this and the holder has inclined surfaces with respect to the support surface. The wedge piece is adjusted lengthwise by means of a in the holder located eccentric arrangement.

The setting of this known holder is done with the help of a Special device, for which the holder can be removed from the boring bar got to. In the operating position on the boring bar, an on or Adjustment does not take place because the holder together with the wedge piece the boring bar is screwed tight, so that then no relative movement between the holder and the wedge piece is more possible.

From DE-OS 16 27 021 an adjustable boring bar is known in the a cutting plate is attached to a holder, the holder itself with screws, the orthogonal to the axis of rotation of the boring bar in the base body of the Tool shaft are arranged, is screwed tight. In front of the Boring bar is parallel to the holder and to the axis of the boring bar arranged a screw that is movable in a thread of the base body is and a spherical sliding body in the axial direction of the boring bar emotional. This causes the cutting tip to be deflected radially outwards for generation larger drilling diameter. This arrangement has several disadvantages Screwing the holder with two screws is complicated an axial It is not possible to move the holder to e.g. stepped holes contribute. Due to the parallel displacement of the crowned Slider is the point of attack for the deflection of the holder and thus the Cutting insert variable in terms of its fixed points to the base body. Thereby results at a certain angle of rotation of the adjusting screw different radial deflection of the insert. A setting in the µm range can not.

A generic state of the art is known from DE 35 30 696 A1, in which a deflection of the under tension with the help of a parallel spring there is possible cutting plate screwed onto the resilient holder. The Holder itself is by welding or otherwise using a cassette-like Base of the holder, the spring and its adjusting device connected so that a preset cassette can be completely installed in a boring bar can. The insert can also be installed in the cassette be adjusted. It creates problems with such systems, small To create holes, since the cassette itself has dimensions that is not suitable for small holes. Furthermore is also through the Adjustment screw to first move a wedge body, which in turn is then adjusted the holder. This arrangement inevitably results in a additional game; the stick-slip effect is reduced to a minimum, however, at most, radial adjustments in the range of 10 µm or reach bigger.

The same applies to the cassette-like arrangement according to DE 22 35 782 C2, with a cassette under spring tension with the help of appropriate Wedge surfaces and pressure screws can be adjusted so that the Drilling diameter is made slightly larger or smaller. Also in in this case the cartridge shape prevents small holes from being made. In addition, the springs do not act primarily against the adjusting device, so that an adjustment at most with an accuracy in the range of a few tenths mm is possible. The effective range of fine boring elements is one Adjustment accuracy of less than 10 µm.

From DE 39 26 026 A1 fine boring heads are known, in which one for small Bores of suitable shaft-like insert carriers against spring action is radially adjustable. Such fine boring heads or fine boring cartridges are however expensive. These fine boring heads cannot be used in one pass create multi-stage bores, which is usually done by short clamps is possible.

The object of the invention is to overcome existing shortcomings and disadvantages overcome and create a tool like a short clamp, the ready for use a slight radial adjustment of the Cutting insert permitted in the accuracy range of a few µm, namely without the so-called setting angle (kappa) being an impermissible change experiences. The tool should also be simple and designed in particular, also build relatively small, so that even under cramped space can be used, especially as Feinbohrelement. Related to all of these other problems with which the invention is concerned with, result from the respective explanation the solution shown.

The two solutions of the invention result from that in claims 1 and 3 specified features. Developments of the invention are in the Subclaims recorded.

Such a tool represents a small unit. Its Dimensions can be chosen so that it is also for small Borehole diameter is suitable. There is also an axial one Realize adjustability, as is often necessary, e.g. to produce stepped bores. With all of this, it stands out Tool but through a particularly advantageous adjustability in radial Direction out, without influencing other people Size, especially the setting angle. This is in one Embodiment by the design of the holder as a parallel spiral spring arrangement reached. This is to be understood as a configuration in which under Application of an elastic bend of parts of the holder's head part, i.e. the part carrying the insert, essentially one Experiencing parallel shift to yourself.

The training can be made so that the holder in the deflected state in is essentially unloaded and an elastic restoring force that one Counteracts deflection, arises only when the adjustment device is off is operated from a zero or starting position. With a special advantage but the holder is already in the undeflected state Preload is maintained so that there is no play from the outset is. This can be achieved in that the holder forming a spring is fixed is screwed to the base body and directly on the Set screw is present.

For the opening provided for this parallel spring design there are various execution options, especially those with Recess in the corner areas that prevent notch stresses. At a very favorable embodiment, the opening has essentially the Shape of a U with a central fastening tongue.

The adjusting device is designed as a screw which engages in a thread of the base part and is supported on the base part. In a particularly expedient embodiment, the set screw with the holder has such a wedge surface pairing that self-locking cannot occur. This allows the wedge surfaces to slide when the screw is turned in the loosening direction due to the high preload, ie the holder always remains in contact with the screw.
The wedge surface pairing between the holder and the adjusting screw can be produced, for example, by a spherical or conical section of the screw, paired with a vertical section of the holder, or vice versa, or by mixed forms. The direct contact of the elements and their direction of action is important.
With such an adjustment device, it is possible to deflect the cutting insert radially more finely than 3 μm and to produce correspondingly accurate bores. The repetition accuracy is so precise that the movement of the adjusting screw on an annular scale arranged thereon relative to a reference point on the base body can be assigned to a corresponding radial adjustment of the cutting edge. A radian measure of 1mm on the screw corresponds to 1/1000 mm on the cutting edge. This repeat accuracy is a prerequisite for complying with the quality conditions required by DIN / ISO 9000 ff with inexpensive tools such as a standard short clamp. The requirement here is a setting accuracy of 10 µm or finer. The smallest feasible drilling diameter is around 10 mm.

A second and cheaper variant of the solution allows a delivery of 5 to or finer too. Here is the holder with a very instead of a parallel spring stiff spring, preferably a disc spring, fixed to the base body. The Adjustment device is designed like the first solution and it adjusts the Holder by radial deflection of the cutting tip against the action of the Belleville spring. The fastening screw for the holder is in Arranging orthogonal direction to the axis of rotation of the tool can however to the direction of deflection in the level of the top of the insert by 0 ° - 45 ° be pivoted if this is necessary for design reasons.

The adjusting screw is in any case approximately vertical to the axis of rotation and about vertical to the insert level and is as close as possible behind the The cutting edge is arranged to directly adjust the adjusting force without large moments To be able to exercise holder at the level of the cutting plate.

This takes into account a market demand, inexpensive Tools for mass production with high functional accuracy and To provide production security. With the invention, a DIN standard Short clamp holders can be modified so that with this tool a defined fine adjustment of the insert is possible.

Figur 1

einen standardisierten Kurzklemmhalter mit schematischer Darstellung einer erfindungsgemäßen Anordnung;

Figur 2

eine vergrößerte Draufsicht mit Teilschnitt in geringfügig modifizierter Ausführung analog Figur 1;

Figur 3

einen Schnitt III - III gemäß Figur 2 durch eine erfindungsgemäße Werkzeuganordnung;

Figur 4

eine Draufsicht auf eine zweite Lösung der Erfindung;

Figur 5

einen Schnitt V - V gemäß Figur 4.

Further details and advantages of the invention result from the following explanation of exemplary embodiments and the associated drawing. Show it:

Figure 1

a standardized short clip holder with a schematic representation of an arrangement according to the invention;

Figure 2

an enlarged plan view with partial section in a slightly modified version analogous to Figure 1;

Figure 3

a section III - III of Figure 2 through an inventive tool assembly;

Figure 4

a plan view of a second solution of the invention;

Figure 5

a section V - V according to Figure 4.

Figure 1 shows a short clamp with machine shaft 1 and Tool shank 2 with holder 5, on which a cutting plate 3 is screwed 4 is fixed. The holder is together with a cover 7 Screw 6 fixed in tool shank 2 and supported against an edge 9 of the Tool shank. The adjusting screw 8 allows a deflection of the Cutting plate 3 in order to create a slightly different radius Adjust bore.

Figure 2 shows the tool shank 2 analogous to Figure 1 with its axis A, the is at the same time the axis of rotation, the tool using the Cutting plate 3 creates a bore 10 through in diameter Deflection of the cutting plate in the direction R is variable. The deflection of the Cutting plate in the direction R is done by the screw 8 (Figure 3), which on a threadless part 15 in contact with a complementary one Pressure zone 18 of the holder 5 is. By adjusting the screw with the conical pressure zone 15 (Figure 3) in the direction Z of the threaded hole 13 in Base body and corresponding displacement of the threaded pin 14 Screw 8 in this threaded hole moves the pressure zone 15 in the Z direction and so presses on the pressure zone 18 of the holder 5 with the result of a radial Adjustment of the cutting plate 3. The pressure zone 15 is supported with it the holder opposite shoulder 19 on the body part 12 of the Tool shank. The holder 5 consists essentially of one part which the cutting plate 3 is attached and two legs s, limited by one U-shaped joint F on three sides of the central tongue 17, the Relaxation holes 16 connects together and so a parallel spring forms. The tongue 17 is by means of screw 6 in the base part 12 of the Tool shaft 2 fixed, the insert 3 due to the Joint arrangement can execute a parallel movement in direction R, as far as the adjustment of the set screw 8 makes this possible. Across from Tool shaft 2, the holder 5 is adjustable in the axial direction, so that the Cutting plates in a specific position relative to the tool shank 2 to be able to position. This is useful if, for example, on the opposite side of the tool shank 2 a further insert arranged at a different axial distance from the head of the tool shank to create a two-stage hole. So a certain Axial adjustment by screw 9 is possible, screw 6 sits an elongated hole in the tongue 17. The parallel spring or the holder 5 is through a cover 7 so that the joint F is not covered by chips and Foreign bodies can be added.

FIG. 4 shows the second solution of the invention analogously to FIG. 2. The Tool shaft 21 with axis A carries a holder 22 with bore 29 through the the holder with the interposition of a plate spring 26 with a screw 27 (Fig. 5) can be fixed to the shaft 21 as soon as the spacer screw 28 is set for the axial position of the cutting edge 31. The adjusting screw 23 is at a short distance H behind the cutting edge on the back of the Holder arranged in the shaft 21. Fig. 5 according to section V-V in Fig. 4 indicates the screw 23 a threadless crowned section 30 on a Complementary wedge surface 24 presses on the holder 22 and so an adjustment of Cutting edge 31 from radius R1 for bore 20 to radius R2 enables. The Adjustment takes place against the restoring force of the spring 26, so that a constant contact of the wedge surface pairing in the pressure zones of Adjusting screw and holder (reference numbers 30, 24) is guaranteed. Here too the head of the screw 23 can be provided with a scale that at corresponding radial angle indicates the radial adjustment.

In both solutions according to the invention, the thread of the Adjustment screw itself and / or the complementary thread in the shaft largely set free of play or by special measures such as HELICOIL inserts, slitting the threaded bushing or coating, Treating the thread flanks, the thread pairing made free of play.

Claims (8)

1. Rotary tool (1, 2) for metal-cutting purposes, having a holder (5) which includes, in its front part (2), at least one receiving means for a cutting plate (3) and, in the region between its ends, a hole for a securing screw (6) to pass therethrough, by means of which screw said holder is securable on a carrier (2), more especially a drilling rod, the holder (5) being, at its part carrying the cutting plate (3), resiliently deflectable relative to a support (2, 12) by means of an adjusting device, the holder (5) being provided with an opening (16, F) and forming a parallel spiral spring arrangement (5 - 9, 16, 17, F, s) so that the cutting plate (3), during its adjustment, experiences substantially a parallel displacement (R) relative to the cutting edge, characterised in that the adjusting device is in the form of adjusting screw (8), which extends through the carrier (2) directly behind the holder (5) and has, on a threadless circumferential member between the support (12, 19) in the carrier (2), on the one hand, and a thread (13) in the carrier for a thread (14) of the adjusting screw (8), on the other hand, a pressure zone (15) which forms a pair of wedge surfaces, which is subject to initial tension, jointly with a complementary pressure zone (18) on the holder (5).
2. Tool according to claim 1, characterised in that the opening (F) is substantially U-shaped.
3. Rotary tool for metal-cutting purposes, having a holder (22) which includes, in its front part, at least one receiving means for a cutting plate (31) and, in the region between its ends, a hole (29) for a securing screw (27) to pass therethrough, by means of which screw said holder is securable on a carrier (21), more especially a drilling rod, the holder (22) being, at its part carrying the cutting plate (31), deflectable relative to a support (21) by means of an adjusting device, characterised in that the securing screw (27) is screwed into the carrier (21) in opposition to a strong spring (26), preferably a plate spring, the adjusting device is in the form of adjusting screw (23), which has, on a threadless circumferential member (30), a pressure zone which forms a pair of wedge surfaces jointly with a complementary zone (24) on the holder (22), and the shaft of the securing screw (27) is disposed in the orthogonal direction relative to the axis of rotation (A) of the tool and at 0° - 45° relative to the direction of deflection of the cutting plate (31).
4. Tool according to claim 1 or 3, characterised in that the holder (5, 22) is screw-connected to the basic body member (2, 21) with initial tension.
5. Tool according to one of the preceding claims, characterised in that the wedge surface (18, 24) is provided at the pressure zone of the holder (5, 22), and the pressure zone (15, 30) of the screw (8, 23) is cylindrical or spherical.
6. Tool according to one of the preceding claims, characterised in that the wedge surface pairing (15, 18; 24, 30) between holder (5, 22) and adjusting screw (8, 23) is formed by a spherical or conical portion of the screw, paired with a vertical portion of the holder, or vice versa, or by mixed shapes.
7. Tool according to one of the preceding claims, characterised in that the wedge surface pairing is reversible.
8. Tool according to one of the preceding claims, characterised in that an annular scale is provided on the head of the adjusting screw (8, 23), and a reference mark for the scaling is provided on the basic body member (2, 21).

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